Essential tremor (ET), a neurological disorder characterized by shaking and trembling of the hands or the head, may be very disabling. Patients with this disorder may experience difficulty with handwriting, drinking liquids, and other activities that require steady hands. Unfortunately, the precise extent of the disabilty associated with this disorder has never really been studied adequately. In this study, we will determine the extent and type of disability associated with ET. This will be done in several ways, including questionnaires (to assess subjective complaints of functional handicap or disability). The functional capabilities will be compared in ET cases and control subjects of similar age. 318 study subjects consisting of ET cases (N=159) and control subjects of similar age (N=159), will be enrolled. Each study subject will be evaluated once. The 2-2.5 hour evaluation, conducted either at the patient's home or at the medical center, will consist of interviews, an examination to assess tremor severity, performance-based assessments of function (e.g. asking the subject to pour water, use a spoon, draw a spiral, etc.), and a quantitive computerized tremor analysis to quantify tremor severity.